EP0593535A1 - Patella prostheses - Google Patents

Patella prostheses

Info

Publication number
EP0593535A1
EP0593535A1 EP92913486A EP92913486A EP0593535A1 EP 0593535 A1 EP0593535 A1 EP 0593535A1 EP 92913486 A EP92913486 A EP 92913486A EP 92913486 A EP92913486 A EP 92913486A EP 0593535 A1 EP0593535 A1 EP 0593535A1
Authority
EP
European Patent Office
Prior art keywords
patella
prosthesis
patella prosthesis
contours
polyethylene
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92913486A
Other languages
German (de)
French (fr)
Inventor
David Paul Johnson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0593535A1 publication Critical patent/EP0593535A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/306—Other specific inorganic materials not covered by A61L27/303 - A61L27/32
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/38—Joints for elbows or knees
    • A61F2/3877—Patellae or trochleae
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/28—Materials for coating prostheses
    • A61L27/30—Inorganic materials
    • A61L27/32—Phosphorus-containing materials, e.g. apatite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A61F2/30942—Designing or manufacturing processes for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2310/00—Prostheses classified in A61F2/28 or A61F2/30 - A61F2/44 being constructed from or coated with a particular material
    • A61F2310/00389—The prosthesis being coated or covered with a particular material
    • A61F2310/00592—Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
    • A61F2310/00796—Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L2430/00—Materials or treatment for tissue regeneration
    • A61L2430/24—Materials or treatment for tissue regeneration for joint reconstruction

Definitions

  • Patella prostheses This invention relates to surgical devices and is concerned with a prosthetic patella replacement for use as a surgical implant.
  • the surgical management of arthritis of the knee involves external supports such as bandages, braces and walking aids.
  • Operative intervention may include anaes ⁇ thetic, intra-articular steroid injection or radio-isotope synovectomy, arthroscopic washout, debridement, menisectomy, chondroplasty or synovectomy, esteotomy or an arthroplasty.
  • Joint arthroplasty may be an excision arthroplasty or interpositional or fascial arthroplasty or a prosthetic arthroplasty.
  • Prosthetic arthroplasty of the knee may be undertaken as a uni-compartmental arthroplasty, a bi- compartmental arthroplasty, a patello-femoral arthroplasty or a total knee arthroplasty.
  • the total knee arthroplasty may be subdivided into a hinged or linked arthroplasty although this has been superseded by the total condylar arthroplasty which may be unconstrained, semi-constrained or constrained according to the freedom of motion conferred upon the arthroplasty by its design (Goodfellow and O'Connor 1986) .
  • Patello-Femoral replacement was not initially performed as a part of total knee arthroplasty (Sneppen et al 1978) .
  • the anterior surface of the femur was left uncovered articulating directly with the patella. This resulted in unacceptable knee pain and poor function. Therefore modifi ⁇ cations were introduced which resurfaced the anterior surface of the femur (Insall et al 1976) . This still resulted in unacceptable anterior knee pain and poor function. Therefore a patella prosthesis was developed which was initially a polyethylene dome shape fitting flush on top of the patella after the articular surface was resected
  • the wear rate progresses through the thin polyethylene at an earlier stage, the metal backing may then be exposed and cause squeaking or scratching of the implant and metallic debris may be added to the plentiful polyethylene debris produced.
  • the manufacture of the metal backing has been difficult, leading to disruption of the pegs from its reverse side.
  • the metal backing and the polyethylene may become dissociated, and manufacture of a harder carbon fibre impregnated polyethylene patella dome has led to excessive wear, release of carbon fibre into the knee and disruption of the polyethylene due to faulty manufacture. Patella fracture or dislocation may also occur and this may be more common with the thicker designs of patella implant or where insufficient patella bone is resected (Scott et al 1978. inzuki and Schurman 1979, Clayton and Thirupathi 1982, Ranawat 1986, Simison, Noble and Hardinge .1986, Lynch, Rorabeck and Bourne 1987) .
  • the patella is a torque converter between the pull vertically of the quadriceps muscle and the patella tendon acting on the tibial to extend the knee joint.
  • the patella articulates at its thickest inferior pole in knee extension thus maintaining the point of articulation within the depth of the patella groove distally where it is more stable, but also shifting the quadriceps tendon anteriorly thus in ⁇ creasing the moment around the knee and generating a greater extension force on the tibia near full extension. This produces an advantageous mechanical advantage to the quadriceps and also confers greater stability to the patello-femoral joint.
  • the human patella during knee flexion articulates upon its medial and lateral edges, so allowing the patella to sink between the femoral condyles and a greater range of knee flexion for a given quadriceps flexibility.
  • the articulation on the patella shifts to the superior portion which is thinner and allows sinkage between the condyles. But it also allows less patella flexion during knee flexion and hence further knee flexion for a given quadriceps flexibility (Ritter and Campbell 1987) .
  • the aim of the invention is to design an implant using materials which will be subject to less wear, less subject to disintegration under stress, and less likely to become disrupted from any metal backing. It should also allow a greater thickness of the implant to prolong its longevity, but without increasing the thickness of the whole patella- implant complex and without weakening the construction. It should further be possible to allow un-cemented insertion of the implant, and further objects are to enable reconst ⁇ ruction of the anatomical patella to have a shape which allows sinkage between the condyles during knee flexion, to minimise the patella flexion during knee flexion, to increase the extensor moment during knee extension, and to increase patello-femoral stability.
  • a patella prosthesis comprising a generally mushroom shaped member whose stem is received in a counter- sunk hole in the surface of a re-sectioned patella articular surface.
  • the preferred materials are polyethylene and high purity alumina ceramic.
  • a metal backing with a porous surface may be provided on the inferior side of the prosthesis. Also, a hydroxyapat- ite coating may be applied to this side, either to the main material or to the metal backing if that is provided.
  • the prosthesis is symmetrical about the axis of the mushroom-shaped member.
  • the head of this member asymmetrical and shaped to follow closely the contours of the human patella.
  • a method of manufacturing a patella prosthesis comprising scanning a patient's patella to make a record of the contours and then constructing a patella prosthesis using said record to reproduce the contours on a workpiece.
  • patella prosthesis will of course be as defined above.
  • a method of implanting a patella prosthe- sis comprising carrying out a patella articular resection, drilling the surface thus formed, and implanting a patella prosthesis as defined above with the stem inserted in the drilling.
  • Figure 1 is an inferior view of a patella dome
  • Figures 2 and 3 are lateral views of a patella dome such as that of Figure l
  • Figure 4 is a coronal view of a patella dome for improved torque conversion
  • Figure 5 is a sagittal view of the dome of Figure 4
  • Figure 6 is a coronal view of another torque converter patella dome
  • Figure 7 is a sagittal view of the dome of Figure 6.
  • domes are generally of squat mushroom shape with a head 1 and a stem 2. They differ primarily in the contours of the head and in the materials in which they are made. Typically, the diameter of the head might be 20-30 mm, the depth of the head from crown to the end of the slope 6-
  • the dome of the patella prosthesis is of conventional symmetrical shape.
  • It can be manufactured from polyethylene or from high purity alumina ceramic. The latter is particularly resistant to wear and so the production of wear debris and disruption is minimised.
  • patella articular surface resection After patella articular surface resection the surface is further drilled to allow the stem 2 to be countersunk, thus providing an implant with a thicker articular surface whilst not increasing the overall thicknes of the construct.
  • a third version has a hydroxyapatite coating to the narrow cylindrical edge 3 and inferior side 4 of the head 1 and to the stem 2, thus allowing for tissue integration and uncemented use.
  • a fourth version, shown in Figure 3, is generally similar in overall dimensions but has an incorpor ⁇ ated metal backing 5 with a porous metal surface (which may not extend over the stem 2) and hydroxyapatite coating, for uncemented use.
  • a second type of patella implant shown in Figures 4 and 5 and in Figures 6 and 7, is modified from the first type described above by having an eccentric dome more akin to the shape of the human patella. This I refer to as the
  • Patella Dome' TPD
  • TPD Tetra-Torque Converter Patella Dome'
  • it can be manufactured from polyethylene or high purity alumina ceramic, with or without a hydroxyapatite coating to the sides and base, or (as in Figures 6 and 7) with a ceramic articulating surface having a metal backing with a porous surface and a hydroxyapatite coating.
  • a third type of patella implant is for patients who have isolated patello-femoral arthritis at an early age and in whom total condylar knee arthroplasty can be avoided by patella resurfacing in isolation.
  • the three dimensional anatomy of a patient's patella is taken from a scan of the patella, either from the pictures of a computerised tomog ⁇ raphy scan or alternatively a magnetic resonance imaging scan of the in situ arthritic patella.
  • What I refer to as an 'Elite Custom Patella Dome' (ECPD) is then constructed by computer assisted manufacturing techniques for implantation in the patient.
  • Each implant is therefore a customised model of the patient's original patella. In materials and appear ⁇ ance there will not be any great difference between this type and the second type of Figures 4 to 7 and therefore they are not illustrated.

Abstract

Prothèse de rotule constituée par un élément en forme de champignon, dont la tête (1) est symétrique ou correspond au profil d'une rotule humaine. La tige (2) s'introduit dans un perçage effectué dans la surface reséquée et conçue pour recevoir la surface inférieure (4) de la tête (1). On utilise de préférence un matériau en polyéthylène ou en céramique d'oxyde d'aluminium à pureté élevée et ou on peut placer un support métallique de renforcement (5) à surface poreuse recouvrant le côté inférieur (4). On peut également utiliser, à cet emplacement, un revêtement en hydroxyapatite.Patella prosthesis constituted by a mushroom-shaped element, the head (1) of which is symmetrical or corresponds to the profile of a human patella. The rod (2) is inserted into a hole made in the resected surface and designed to receive the lower surface (4) of the head (1). Preferably, a polyethylene or aluminum oxide ceramic material of high purity is used and or a metallic reinforcing support (5) with a porous surface covering the lower side (4) can be placed. A hydroxyapatite coating can also be used at this location.

Description

Patella prostheses This invention relates to surgical devices and is concerned with a prosthetic patella replacement for use as a surgical implant. The surgical management of arthritis of the knee involves external supports such as bandages, braces and walking aids. Operative intervention may include anaes¬ thetic, intra-articular steroid injection or radio-isotope synovectomy, arthroscopic washout, debridement, menisectomy, chondroplasty or synovectomy, esteotomy or an arthroplasty.
Joint arthroplasty may be an excision arthroplasty or interpositional or fascial arthroplasty or a prosthetic arthroplasty. Prosthetic arthroplasty of the knee may be undertaken as a uni-compartmental arthroplasty, a bi- compartmental arthroplasty, a patello-femoral arthroplasty or a total knee arthroplasty. The total knee arthroplasty may be subdivided into a hinged or linked arthroplasty although this has been superseded by the total condylar arthroplasty which may be unconstrained, semi-constrained or constrained according to the freedom of motion conferred upon the arthroplasty by its design (Goodfellow and O'Connor 1986) .
Patello-Femoral replacement was not initially performed as a part of total knee arthroplasty (Sneppen et al 1978) . The anterior surface of the femur was left uncovered articulating directly with the patella. This resulted in unacceptable knee pain and poor function. Therefore modifi¬ cations were introduced which resurfaced the anterior surface of the femur (Insall et al 1976) . This still resulted in unacceptable anterior knee pain and poor function. Therefore a patella prosthesis was developed which was initially a polyethylene dome shape fitting flush on top of the patella after the articular surface was resected
(Moreland Thomas and Freeman 1979) . A small keel or peg fitted down in the cancellous bone of the patella to stabilise the prosthesis onto the bone. This patella dome was cemented in situ with acrylic cement (Insall, Lachiewich and Burstein 1982, Wright et al 1990).
As un-cemented prostheses became popular in the early 1980's the design of the patella was changed in most implants (Hungerford and Krackow 1985) . The basic concept was unaltered. However a metal back was attached to the implant to reduce deformation of the polyethylene, to allow initial fixation without acrylic cement and to allow bone ingrowth into the porous metal backing of the patella thus giving long term stability within the bone (Kenna and Hungerford 1984) . However the recent reports now emerging throughout the world refer to great problems with such a design. As the polyetheylene thickness is reduced to allow for the metal backing, the polyethylene becomes liable to disintegrate under the stresses to which it is submitted. The wear rate progresses through the thin polyethylene at an earlier stage, the metal backing may then be exposed and cause squeaking or scratching of the implant and metallic debris may be added to the plentiful polyethylene debris produced. The manufacture of the metal backing has been difficult, leading to disruption of the pegs from its reverse side. The metal backing and the polyethylene may become dissociated, and manufacture of a harder carbon fibre impregnated polyethylene patella dome has led to excessive wear, release of carbon fibre into the knee and disruption of the polyethylene due to faulty manufacture. Patella fracture or dislocation may also occur and this may be more common with the thicker designs of patella implant or where insufficient patella bone is resected (Scott et al 1978. ochizuki and Schurman 1979, Clayton and Thirupathi 1982, Ranawat 1986, Simison, Noble and Hardinge .1986, Lynch, Rorabeck and Bourne 1987) .
The incidence of patello-femoral complications foll¬ owing knee arthroplasty is now the most common complication and has been reported as being up to 64% of cases (Sneppen et al 1978, Clayton and Thirupathi 1982, Merkow, Soudry and Insall 1985, Scuderi et al 1989)-.
Another factor which has received little attention is the shape of the articulating surface in relation to patello-femoral stability in the lateral plane. It is accepted that the anterior flange of the femoral component must be long enough to prevent lateral tracking or soft tissue impingement (Sneppen et al 1978, Thorpe, Bocell and Tullos 1990) . Hungerford suggested an anatomical shape of patella button with the maximal thickness placed laterally. However the use of this implant fell into disrepute with the difficulties of insertion and high complication rate (Kenna and Hungerford 1984, Hungerford and Krackow 1985). Recently a design has been released with a central post and a surroundng shelf at a lower level. This was produced to aid patello-femoral stability by increasing the lateral resis¬ tance to patella subluxation from the patello-femoral groove. The incidence of patello-femoral complications has led many surgeons to abandon patella resurfacing (Scott et al 1978, Picetti, McGann and Welch 1990).
There has been little concern with the mechanics of the human patella in relationship to the articular geometry. Thus the patella is a torque converter between the pull vertically of the quadriceps muscle and the patella tendon acting on the tibial to extend the knee joint. The patella articulates at its thickest inferior pole in knee extension thus maintaining the point of articulation within the depth of the patella groove distally where it is more stable, but also shifting the quadriceps tendon anteriorly thus in¬ creasing the moment around the knee and generating a greater extension force on the tibia near full extension. This produces an advantageous mechanical advantage to the quadriceps and also confers greater stability to the patello-femoral joint.
The human patella during knee flexion articulates upon its medial and lateral edges, so allowing the patella to sink between the femoral condyles and a greater range of knee flexion for a given quadriceps flexibility. The articulation on the patella shifts to the superior portion which is thinner and allows sinkage between the condyles. But it also allows less patella flexion during knee flexion and hence further knee flexion for a given quadriceps flexibility (Ritter and Campbell 1987) .
The aim of the invention is to design an implant using materials which will be subject to less wear, less subject to disintegration under stress, and less likely to become disrupted from any metal backing. It should also allow a greater thickness of the implant to prolong its longevity, but without increasing the thickness of the whole patella- implant complex and without weakening the construction. It should further be possible to allow un-cemented insertion of the implant, and further objects are to enable reconst¬ ruction of the anatomical patella to have a shape which allows sinkage between the condyles during knee flexion, to minimise the patella flexion during knee flexion, to increase the extensor moment during knee extension, and to increase patello-femoral stability.
According to one aspect of the present invention there is provided a patella prosthesis comprising a generally mushroom shaped member whose stem is received in a counter- sunk hole in the surface of a re-sectioned patella articular surface.
The preferred materials are polyethylene and high purity alumina ceramic.
A metal backing with a porous surface may be provided on the inferior side of the prosthesis. Also, a hydroxyapat- ite coating may be applied to this side, either to the main material or to the metal backing if that is provided.
In a simple form, the prosthesis is symmetrical about the axis of the mushroom-shaped member. However, it will generally be preferred to have the head of this member asymmetrical and shaped to follow closely the contours of the human patella. According to another aspect of the present invention there is provided a method of manufacturing a patella prosthesis comprising scanning a patient's patella to make a record of the contours and then constructing a patella prosthesis using said record to reproduce the contours on a workpiece.
Such a patella prosthesis will of course be as defined above.
According to a further aspect of the present invention there is provided a method of implanting a patella prosthe- sis comprising carrying out a patella articular resection, drilling the surface thus formed, and implanting a patella prosthesis as defined above with the stem inserted in the drilling.
For a better understanding of the invention some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is an inferior view of a patella dome, Figures 2 and 3 are lateral views of a patella dome such as that of Figure l, Figure 4 is a coronal view of a patella dome for improved torque conversion,
Figure 5 is a sagittal view of the dome of Figure 4, Figure 6 is a coronal view of another torque converter patella dome, and
Figure 7 is a sagittal view of the dome of Figure 6.
All the domes are generally of squat mushroom shape with a head 1 and a stem 2. They differ primarily in the contours of the head and in the materials in which they are made. Typically, the diameter of the head might be 20-30 mm, the depth of the head from crown to the end of the slope 6-
10 mm, the depth of the shallow cylindrical portion of the head (or edges 3) 3mm, the diameter of the stem 10 mm and its length 4 mm.
In Figures 1 and 2, the dome of the patella prosthesis is of conventional symmetrical shape.
It can be manufactured from polyethylene or from high purity alumina ceramic. The latter is particularly resistant to wear and so the production of wear debris and disruption is minimised.
After patella articular surface resection the surface is further drilled to allow the stem 2 to be countersunk, thus providing an implant with a thicker articular surface whilst not increasing the overall thicknes of the construct.
These two versions are fixed with acrylic cement.
A third version has a hydroxyapatite coating to the narrow cylindrical edge 3 and inferior side 4 of the head 1 and to the stem 2, thus allowing for tissue integration and uncemented use. A fourth version, shown in Figure 3, is generally similar in overall dimensions but has an incorpor¬ ated metal backing 5 with a porous metal surface (which may not extend over the stem 2) and hydroxyapatite coating, for uncemented use.
A second type of patella implant, shown in Figures 4 and 5 and in Figures 6 and 7, is modified from the first type described above by having an eccentric dome more akin to the shape of the human patella. This I refer to as the
'Torque Converter Patella Dome' (TPD) . Again it can be manufactured from polyethylene or high purity alumina ceramic, with or without a hydroxyapatite coating to the sides and base, or (as in Figures 6 and 7) with a ceramic articulating surface having a metal backing with a porous surface and a hydroxyapatite coating.
A third type of patella implant is for patients who have isolated patello-femoral arthritis at an early age and in whom total condylar knee arthroplasty can be avoided by patella resurfacing in isolation. The three dimensional anatomy of a patient's patella is taken from a scan of the patella, either from the pictures of a computerised tomog¬ raphy scan or alternatively a magnetic resonance imaging scan of the in situ arthritic patella. What I refer to as an 'Elite Custom Patella Dome' (ECPD) is then constructed by computer assisted manufacturing techniques for implantation in the patient. Each implant is therefore a customised model of the patient's original patella. In materials and appear¬ ance there will not be any great difference between this type and the second type of Figures 4 to 7 and therefore they are not illustrated.

Claims

1. A patella prosthesis comprising a generally mush¬ room-shaped member whose stem is received in a countersunk hole in the surface of a resectioned patella articular surface.
2. A patella prosthesis according to Claim 1, characterised in that the prosthesis is of polyethylene.
3. A patella prosthesis according to Claim 1, characterised in that the prosthesis is at least substan- tially of high purity alumina ceramic.
4. A patella prosthesis according to Claim 1, 2 or 3, characterised in that a metal backing with a porous surface is provided on the inferior side of the prosthesis.
5. A patella prosthesis according to any preceding claim characterised in that a hydroxyapatite coating is applied to the inferior side of the prosthesis.
6. A patella prosthesis according to any preceding claim, characterised in that it is symmetrical about the axis of the mushroom shaped member.
7. A patella prosthesis according to any one of claims 1 to 5, characterised in that the head of the mushroom shaped member is asymmetrical and shaped to follow closely the contours of a human patella.
8. A method of manufacturing a patella prosthesis comprising scanning a patient's patella to make a record of the contours and then constructing a patella prosthesis using said record to reproduce the contours on a workpiece.
9. A method as claimed in Claim 1, wherein the patella prosthesis is as claimed in Claim 7.
10. A method of implanting a patella prosthesis, the method comprising carrying out a patella articular resec¬ tion, drilling the surface thus formed, and implanting a patella prosthesis as claimed in any one of Claims 1 to 7, or manufactured as claimed in Claim 9, with the stem inserted in the drilling.
EP92913486A 1991-07-05 1992-07-06 Patella prostheses Withdrawn EP0593535A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9114603 1991-07-05
GB919114603A GB9114603D0 (en) 1991-07-05 1991-07-05 Improvements relating to patella prostheses
PCT/GB1992/001226 WO1993000871A1 (en) 1991-07-05 1992-07-06 Patella prostheses

Publications (1)

Publication Number Publication Date
EP0593535A1 true EP0593535A1 (en) 1994-04-27

Family

ID=10697915

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92913486A Withdrawn EP0593535A1 (en) 1991-07-05 1992-07-06 Patella prostheses

Country Status (5)

Country Link
US (1) US5609640A (en)
EP (1) EP0593535A1 (en)
AU (1) AU2223192A (en)
GB (1) GB9114603D0 (en)
WO (1) WO1993000871A1 (en)

Families Citing this family (65)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2114282A1 (en) * 1993-01-28 1994-07-29 Lothar Schilder Multi-layered implant
GB9306898D0 (en) * 1993-04-01 1993-05-26 Ang Swee C Implantable prosthetic patellar components
GB2301032B (en) * 1995-04-07 1999-10-06 David Giorgio Mendes Prosthetic patella implant of the knee joint and reamer
US8234097B2 (en) 2001-05-25 2012-07-31 Conformis, Inc. Automated systems for manufacturing patient-specific orthopedic implants and instrumentation
US8882847B2 (en) * 2001-05-25 2014-11-11 Conformis, Inc. Patient selectable knee joint arthroplasty devices
US8545569B2 (en) * 2001-05-25 2013-10-01 Conformis, Inc. Patient selectable knee arthroplasty devices
US20110071802A1 (en) * 2009-02-25 2011-03-24 Ray Bojarski Patient-adapted and improved articular implants, designs and related guide tools
US8735773B2 (en) 2007-02-14 2014-05-27 Conformis, Inc. Implant device and method for manufacture
US8556983B2 (en) 2001-05-25 2013-10-15 Conformis, Inc. Patient-adapted and improved orthopedic implants, designs and related tools
US8480754B2 (en) 2001-05-25 2013-07-09 Conformis, Inc. Patient-adapted and improved articular implants, designs and related guide tools
US9603711B2 (en) * 2001-05-25 2017-03-28 Conformis, Inc. Patient-adapted and improved articular implants, designs and related guide tools
US8617242B2 (en) * 2001-05-25 2013-12-31 Conformis, Inc. Implant device and method for manufacture
US20070233269A1 (en) * 2001-05-25 2007-10-04 Conformis, Inc. Interpositional Joint Implant
US8771365B2 (en) * 2009-02-25 2014-07-08 Conformis, Inc. Patient-adapted and improved orthopedic implants, designs, and related tools
US20110071645A1 (en) * 2009-02-25 2011-03-24 Ray Bojarski Patient-adapted and improved articular implants, designs and related guide tools
US20090222103A1 (en) * 2001-05-25 2009-09-03 Conformis, Inc. Articular Implants Providing Lower Adjacent Cartilage Wear
DE19816984A1 (en) * 1998-04-17 1999-10-21 Ceramtec Ag Low wear knee-joint prosthesis employing a natural or artificial patella
US6616696B1 (en) 1998-09-04 2003-09-09 Alan C. Merchant Modular knee replacement system
AU772012B2 (en) * 1998-09-14 2004-04-08 Board Of Trustees Of The Leland Stanford Junior University Assessing the condition of a joint and preventing damage
US9289153B2 (en) * 1998-09-14 2016-03-22 The Board Of Trustees Of The Leland Stanford Junior University Joint and cartilage diagnosis, assessment and modeling
US7239908B1 (en) * 1998-09-14 2007-07-03 The Board Of Trustees Of The Leland Stanford Junior University Assessing the condition of a joint and devising treatment
FR2802819A1 (en) * 1999-12-23 2001-06-29 Hubert Hellak Cotyloid prosthesis made entirely from ceramic with calcium phosphate coating
US6712856B1 (en) 2000-03-17 2004-03-30 Kinamed, Inc. Custom replacement device for resurfacing a femur and method of making the same
US6709460B2 (en) * 2000-03-21 2004-03-23 Alan C. Merchant Patellar bearing implant
EP2036495A1 (en) * 2000-09-14 2009-03-18 The Board of Trustees of The Leland Stanford Junior University Assessing condition of a joint and cartilage loss
AU9088801A (en) 2000-09-14 2002-03-26 Univ Leland Stanford Junior Assessing the condition of a joint and devising treatment
DE60232316D1 (en) * 2001-02-27 2009-06-25 Smith & Nephew Inc DEVICE FOR TOTAL KNEE CONSTRUCTION
WO2002087429A1 (en) * 2001-04-27 2002-11-07 Novartis Ag Apparatus for measuring blood glucose concentrations
ATE504264T1 (en) 2001-05-25 2011-04-15 Conformis Inc METHODS AND COMPOSITIONS FOR REPAIRING THE SURFACE OF JOINTS
FR2831426B1 (en) 2001-10-30 2004-07-16 Tornier Sa JOINT IMPLANT AND KNEE PROSTHESIS INCORPORATING SUCH AN IMPLANT
US20030088315A1 (en) * 2001-11-08 2003-05-08 Supinski Robert S Patella replacement apparatus
CA2501041A1 (en) * 2002-10-07 2004-04-22 Conformis, Inc. Minimally invasive joint implant with 3-dimensional geometry matching the articular surfaces
WO2004037119A2 (en) * 2002-10-23 2004-05-06 Mako Surgical Corp. Modular femoral component for a total knee joint replacement for minimally invasive implantation
CN1780594A (en) 2002-11-07 2006-05-31 康复米斯公司 Methods for determining meniscal size and shape and for devising treatment
US20040143338A1 (en) * 2003-01-21 2004-07-22 Brian Burkinshaw Multi-piece modular patellar prosthetic system
EP3187153A3 (en) * 2005-09-30 2017-09-20 ConforMIS, Inc. Bearing implant
EP1951158A4 (en) * 2005-11-21 2010-03-31 Vertegen Inc Devices and methods for treating facet joints, uncovertebral joints, costovertebral joints and other joints
GB0526385D0 (en) 2005-12-28 2006-02-08 Mcminn Derek J W Improvements in or relating to knee prosthesis
US8142509B2 (en) * 2006-01-23 2012-03-27 Smith & Nephew, Inc. Patellar components
US7691149B2 (en) * 2006-05-15 2010-04-06 Biomet Manufacturing Corp. Porous titanium modular revision patella system
US8142510B2 (en) * 2007-03-30 2012-03-27 Depuy Products, Inc. Mobile bearing assembly having a non-planar interface
US8147558B2 (en) * 2007-03-30 2012-04-03 Depuy Products, Inc. Mobile bearing assembly having multiple articulation interfaces
US8764841B2 (en) * 2007-03-30 2014-07-01 DePuy Synthes Products, LLC Mobile bearing assembly having a closed track
US8147557B2 (en) * 2007-03-30 2012-04-03 Depuy Products, Inc. Mobile bearing insert having offset dwell point
US8328874B2 (en) * 2007-03-30 2012-12-11 Depuy Products, Inc. Mobile bearing assembly
WO2009111626A2 (en) 2008-03-05 2009-09-11 Conformis, Inc. Implants for altering wear patterns of articular surfaces
CN102006841A (en) * 2008-03-05 2011-04-06 肯弗默斯股份有限公司 Edge-matched articular implant
US8043375B2 (en) * 2008-03-06 2011-10-25 MoiRai Orthopaedic, LLC Cartilage implants
AU2009246474B2 (en) * 2008-05-12 2015-04-16 Conformis, Inc. Devices and methods for treatment of facet and other joints
US8012217B2 (en) * 2008-07-03 2011-09-06 Fellowship of Orthopaedic Researchers, LLC Talar implants and methods of use
US8696754B2 (en) 2008-09-03 2014-04-15 Biomet Manufacturing, Llc Revision patella prosthesis
US8078440B2 (en) 2008-09-19 2011-12-13 Smith & Nephew, Inc. Operatively tuning implants for increased performance
CA2771555C (en) 2009-08-25 2016-09-13 Fellowship Of Orthopaedic Researchers, Inc. Trochlear implants and methods of use
EP2509539B1 (en) * 2009-12-11 2020-07-01 ConforMIS, Inc. Patient-specific and patient-engineered orthopedic implants
US8690956B2 (en) 2010-08-23 2014-04-08 Fellowship Of Orthopaedic Researchers, Inc. Talar implants and methods of use
US8834574B2 (en) 2010-12-07 2014-09-16 Zimmer, Inc. Prosthetic patella
US9675399B2 (en) 2011-02-14 2017-06-13 Michael D. Ries Patient specific implants and instrumentation for patellar prostheses
US8945135B2 (en) 2011-02-14 2015-02-03 Michael D. Ries Patellar prostheses and instrumentation
EP2754419B1 (en) 2011-02-15 2024-02-07 ConforMIS, Inc. Patient-adapted and improved orthopedic implants
BR112013032144A2 (en) 2011-06-16 2016-12-13 Smith & Nephew Inc surgical alignment using references
CN103598935A (en) * 2013-11-08 2014-02-26 深圳先进技术研究院 Patella prosthesis structure
US10893948B2 (en) 2017-11-02 2021-01-19 Howmedica Osteonics Corp. Rotary arc patella articulating geometry
CN111065028A (en) * 2019-12-27 2020-04-24 歌尔股份有限公司 Vibrating diaphragm ball top, vibrating diaphragm and loudspeaker
US11844697B2 (en) 2020-09-03 2023-12-19 Globus Medical, Inc. Systems and methods for knee arthroplasty
US11730603B2 (en) 2020-09-03 2023-08-22 Globus Medical, Inc. Systems and methods for knee arthroplasty

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1979000739A1 (en) * 1978-03-10 1979-10-04 Biomedical Eng Corp Improved joint endoprosthesis
US4158894A (en) * 1978-03-13 1979-06-26 Worrell Richard V Patellar prosthesis and method of implanting the same
EP0013864B1 (en) * 1979-01-26 1983-10-19 Osteo Ag Knee joint slide prosthesis
DE3332354A1 (en) * 1983-09-08 1985-03-28 Mohammad Dr.med. 2945 Sande Izadpanah Patella prosthesis
GB8530609D0 (en) * 1985-12-12 1986-01-22 Andrew T Replacement joints
FR2615096A1 (en) * 1987-02-06 1988-11-18 Buscayret Christian Patella cartridge endoprosthesis system
DE3885261T2 (en) * 1987-12-21 1994-04-21 Asahi Optical Co Ltd Process for the production of a substrate coated with apatite.
FR2625096B3 (en) * 1987-12-29 1990-03-30 Hummer Jacques TOTAL KNEE PROSTHESIS WITHOUT CEMENT
US4944756A (en) * 1988-02-03 1990-07-31 Pfizer Hospital Products Group Prosthetic knee joint with improved patellar component tracking
US4964867A (en) * 1989-02-03 1990-10-23 Boehringer Mannheim Corp. Patellar prosthesis
US5024670A (en) * 1989-10-02 1991-06-18 Depuy, Division Of Boehringer Mannheim Corporation Polymeric bearing component
US5019104A (en) * 1990-01-16 1991-05-28 Dow Corning Wright Corporation Patellar prosthesis and method of making the same
US5197986A (en) * 1990-04-11 1993-03-30 Mikhail Michael W E Recessed patellar prosthesis
FR2700260B1 (en) * 1993-01-08 1995-04-14 Bouvet Jean Claude Artificial patellar part for knee prosthesis.
US5358529A (en) * 1993-03-05 1994-10-25 Smith & Nephew Richards Inc. Plastic knee femoral implants

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9300871A1 *

Also Published As

Publication number Publication date
GB9114603D0 (en) 1991-08-21
WO1993000871A1 (en) 1993-01-21
US5609640A (en) 1997-03-11
AU2223192A (en) 1993-02-11

Similar Documents

Publication Publication Date Title
US5609640A (en) Patella prostheses
US10383738B2 (en) Tibial component
AU667001B2 (en) Plastic knee femoral implants
JP4240886B2 (en) Tibial component of knee prosthesis
JP4283075B2 (en) Providing method and kit for joint part, cue stick, shoulder arthroplasty
US6916341B2 (en) Device and method for bicompartmental arthroplasty
EP1331904B1 (en) Bimetal tibial component construct for knee joint prosthesis
US4808185A (en) Tibial prosthesis, template and reamer
US5021061A (en) Prosthetic patello-femoral joint
US8771364B2 (en) Tibial tray having a reinforcing member
US7850738B2 (en) Bimetal acetabular component construct for hip joint prosthesis
US7387644B2 (en) Knee joint prosthesis with a femoral component which links the tibiofemoral axis of rotation with the patellofemoral axis of rotation
US20070219638A1 (en) Prosthetic glenoid component
US20100100191A1 (en) Tibial Tray Having a Reinforcing Member
US10052208B2 (en) Surgically implantable knee prosthesis with captured keel
WO2003045287A2 (en) Knee joint prostheses
JPH08294502A (en) Reinforcing apparatus for knee joint
WO2010042941A2 (en) Implants for the treatment of osteoarthritis (oa) of the knee
GB2355935A (en) Unicompartmental knee prosthesis
EP3711714A1 (en) Tibial baseplate for tibial component of a knee prosthesis, tibial component comprising the tibial baseplate and method for manufacturing the tibial baseplate
US20210386553A1 (en) Tibial baseplate for tibial component of a knee prosthesis, tibial component comprising the tibial baseplate and method for manufacturing the tibial baseplate
GB2342582A (en) Unicompartmental knee prosthesis that limits anterior-posterior, medial-lateral and rotational movement

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19940105

17Q First examination report despatched

Effective date: 19950811

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19961113